Here's one: driving along, the brake warning light comes on for a few seconds, then off. Did it one day several times, and at least a couple of times since. Even kinda flickered. Plenty of brake fluid, brakes seem to work fine. As mentioned in another post, I think I'm hearing a noise (bad hearing and this bus makes so many noises), that I'm assuming might be the power steering pump finally going out. Maybe it's brake related, but I'm thinking it just might be an electrical issue. Anyone have similar issues? Maybe there's a mechanical breakdown in the parking brake linkage that's causing a short. Are there likely points under the dash or at the transmission? Raining here, but probably have to crawl underneath.

 

Are you saying the light that tells you the park brake is engaged is coming on then off intermittently? or is there another brake warning light on these trucks? If it's the park brake light have you applied the park brake recently and released it and maybe it's just not 100% released, not enough to have the park brake applied but just enough to activate the 'Brake' light? The park brakes on these truck are known to have issues especially if they are rarely used, they tend to not release well...at least that has been my experience with them.

 

Yeah, I was confused too - the alert light combines two symbols that are listed separately in the Owner's Manual's glossary. One looks like a drum brake and is called the Brake System alert the second is the P that is the Parking Brake alert. Yet, they're the same light on the dash. So further on, the Manual defines the light itself on the Instrument Cluster page:

Brake system warning light: To confirm the brake system warning light is functional, it will momentarily illuminate when the ignition is turned to the on position when the engine is not running, or in a position between on and START, or by applying the parking brake when the ignition is turned to the on position. If the brake system warning light does not illuminate at this time, seek service immediately from your authorized dealer. Illumination after releasing the parking brake indicates low brake fluid level.

At the time, I pulled over and there was plenty of fluid and a thousand miles later the brakes have continued to work fine. So, I'm assuming it's like you say, something in the parking brake wiring. I did try releasing the brake again, even resetting and releasing. I know I saw the light flash again since then, but in general, it's stopped flashing now (I'm not positive it doesn't flash while I'm focused on the road).

I was wondering if it provided an alert that pads were getting thin, because of that drum brake looking symbol, but that owner's manual definition doesn't suggest that. Honestly, I have't inspected it yet since getting back home. Once it quits raining, I look underneath.

 

Perhaps the fluid level sensor is starting to fail?

 

Aaah, thanks for that suggestion. Hadn't thought of that. I'll check it out too. So, to summarize: the brake alert light flickers several times within a couple minutes, then kinda goes away except for a couple of random, short flickers over a couple of days, then pretty much gone as far as I've seen since then over several days and +1000miles. Only thing I've done is use the parking brake a few times since then, always trying to pull the release firmly. But, I need to recheck the fluid level, crawl underneath to check for leaks/wiring issues, and do a visual on the level sensor.

My guess would be a parking brake wiring/mechanical issue...if it was anyone else's truck. My luck it's related back to the power steering pump - doesn't that boost the brakes too? Maybe that's the grinding I think I hear.